canon rumors FORUM

I would say the addition of the extender would be counter-productive, as tubes work better on shorter focal lengths. You'll probably get more magnification with just the 68mm of the Kenko extension tubes with the 100mm macro, as it's getting towards twice life size. The extender would reduce image quality.

I have tried :1DX, 100L, combined with kenko 12 and 20 and 36 and 2XIII.The only way that I could work with this combo was on a tripod and using Helicon software for the focussing and image stacking.Focussing by hand is next to impossible with such a limited DOF.I will post some images later, comparing the 100L as is and with the combo.

I have actually done this. The extension tube is necessary in order to fit the 2x onto the 100L. However, I did not do this because I needed > 1x magnification. If I wanted that I would just use my MP-E 65.

It just happens that this lens + a 2x III makes a decent tube lens for microscope objectives. The objectives I use require a 200mm lens and my 70-200/2.8 II has too much vignetting. Some day I'll probably pick up the 200/2.8 which does this natively.

I use this with a Nikon 10x and a Mitutoyo 20x. Here's a shot with the Nikon. Someday I'll have enough patience to hook my Stackshot up to it and do stacking.

I have tried :1DX, 100L, combined with kenko 12 and 20 and 36 and 2XIII.The only way that I could work with this combo was on a tripod and using Helicon software for the focussing and image stacking.Focussing by hand is next to impossible with such a limited DOF.I will post some images later, comparing the 100L as is and with the combo.